Azo dyes

ABSTRACT

The present invention relates to an azo dye of formula (I) wherein R 1  and R 2  are each independently of the other —NH—(CH 2 CH 2 )—OH, —NH—CH 2 —CHOH—CH 2 —OH, —NH—(CH 2 CH 2 )—S—(CH 2 CH 2 )—OH, —NH—(CH 2 CH 2 )—NH—(CH 2 CH 2 )—OH, NH—CH 2 CH 2 —CON(CH 2 CH 2 OH) 2 , R 3  is —CN or —CONH 2 , R 4  is methyl or trifluoromethyl, R 5  is —CF 3 , —COOC 2 H 5 , R 6  is hydrogen or chlorine and R 7  is hydrogen, chlorine, bromine or —NO 2 , to a process for the preparation thereof and to the use thereof in a method of producing mass-coloured plastics or polymeric colour particles

The present invention relates to novel azo dyes, to a process for thepreparation thereof and to the use thereof in a method of producingmass-coloured plastics or polymeric colour particles, and of colouringor printing semi-synthetic or synthetic hydrophobic fibre materials.

Dyes for mass-colouring plastics are known. For example there aredescribed in U.S. Pat. No. 5,367,039 1,4,5,8-tetrasubstitutedanthraquinones having (meth)acryloyl groups which can be copolymerisedwith vinyl monomers and are thus suitable for the production of colouredvinyl polymers.

The dyes used until now do not, however, meet the highest requirementsin terms of light fastness and, especially, thermostability.

There is accordingly a need for novel thermostable dyes that producecolorations having a high tinctorial strength and exhibiting lightfastness, especially high-temperature light fastness, and that have goodall-round fastness properties.

U.S. Pat. No. 3,998,802 discloses 2,6-diaminopyridine-based azo dyesthat are suitable for colouring synthetic polyamides and polyestersaccording to the exhaust process and that are distinguished by goodproperties of fastness to heat setting and to light.

It has now, surprisingly, been found that specific2,6-diaminopyridine-based azo dyes are suitable for mass-colouringsynthetic polymers, yield colorations having a high tinctorial strengthand exhibiting light fastness, especially high-temperature lightfastness, and have good all-round fastness properties.

The present invention relates to an azo dye of formula I

wherein R₁ and R₂ are each independently of the other —NH—(CH₂CH₂)—OH,—NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

-   R₃ is —CN or —CONH₂,-   R₄ is methyl or trifluoromethyl,-   R₅ is —CF₃, —COOC₂H₅,

-   R₆ is hydrogen or chlorine and-   R₇ is hydrogen, chlorine, bromine or —NO₂.

The substituents R₁ and R₂ may be identical or different; preferably, R₁and R₂ are identical.

Preference is given to azo dyes of formula I wherein R₃ is —CN and R₄ ismethyl.

Preference is given also to azo dyes of formula I wherein R₁ and R₂ are—NH—(CH₂CH₂)—OH or

Preference is given furthermore to azo dyes of formula I wherein R₇ ishydrogen.

In formula I, R₈ is preferably hydrogen.

Especially preferred azo dyes of formula I are the compounds Ia, Ib, Icand Id:

The compounds of formula I can be prepared according to known methods,for example by diazotization of aromatic amines and a subsequentcoupling reaction.

The invention relates also to a process for the preparation of an azodye of formula (I) which comprises diazotizing a compound of formula II

wherein R₅, R₆ and R₇ are as defined hereinabove, in accordance with aconventional method, and then coupling the diazotized compound to acoupling component of formula III

wherein R₁, R₂, R₃ and R₄ are as defined hereinabove.

The diazotization of the compound of formula (II) is carried out in amanner known per se, for example with sodium nitrite in an aqueousacidic medium, for example an aqueous hydrochloric acid medium oraqueous sulfuric acid medium. The diazotization can, however, also becarried out using other diazotizing agents, for example nitrosylsulfuricacid. An additional acid may be present in the reaction medium in thediazotization procedure, e.g. phosphoric acid, sulfuric acid, aceticacid, propionic acid, hydrochloric acid or a mixture of such acids, forexample a mixture of propionic acid and acetic acid. The diazotizationis advantageously carried out at temperatures from −10 to +30° C., e.g.from 0° C. to room temperature.

Coupling of the diazotized compound of formula (II) to the couplingcomponent of formula (III) is likewise carried out in known manner, forexample in an aqueous acidic medium or aqueous organic medium,advantageously at temperatures from −10 to 30° C., especially below 10°C. The acid used may be, for example, hydrochloric acid, acetic acid,propionic acid, sulfuric acid or phosphoric acid.

The compounds of formula (II) are known or can be prepared in a mannerknown per se.

The coupling components of formula (III) are likewise known or can beprepared in a manner known per se, for example by reacting a2,6-dichloropyridine derivative of formula IV

with an appropriate amine.

The invention relates also to a method of producing mass-colouredplastics or polymeric colour particles which comprises mixing a highmolecular weight organic material with a tinctorially effective amountof at least one azo dye of formula (I).

The colouring of the high molecular weight organic substances using theazo dye of formula (I) is carried out, for example, by using roll mills,mixing apparatus or grinding apparatus to admix such a dye with suchsubstrates, the dye being dissolved or finely distributed in the highmolecular weight material. The high molecular weight organic materialwith the admixed dye is then processed according to methods known perse, such as, for example, calendering, compression moulding, extrusion,coating, spinning, pouring or injection moulding, as a result of whichthe coloured material acquires its final form. Admixture of the dye canalso be effected immediately prior to the actual processing step, forexample by simultaneously continuously feeding, directly into the intakezone of an extruder, a solid, for example pulverulent, dye and agranulated or pulverulent high molecular weight organic material and,where appropriate, also other ingredients, such as additives, theconstituents being mixed in just before being processed. Generally,however, preference is given to mixing the dye into the high molecularweight organic material beforehand, since more uniformly colouredsubstrates can be obtained.

In order to produce non-rigid shaped articles or to reduce theirbrittleness, it is frequently desirable to incorporate so-calledplasticisers into the high molecular weight compounds prior to shaping.There may be used as plasticisers, for example, esters of phosphoricacid, phthalic acid or sebacic acid. In the method according to theinvention, the plasticisers can be incorporated into the polymers beforeor after the incorporation of the colorant. It is also possible, inorder to achieve different colour shades, to add to the high molecularweight organic substances, in addition to the azo dye of formula I, alsoother pigments or other colorants in the desired amounts, optionallytogether with further additives, for example fillers or siccatives.

Preference is given to the colouring of thermoplastic plasticsespecially in the form of fibres. Preferred high molecular weightorganic materials that can be coloured in accordance with the inventionare very generally polymers having a dielectric constant ≧2.5,especially polyester, polycarbonate (PC), polystyrene (PS), polymethylmethacrylate (PMMA), polyamide, polyethylene, polypropylene,styrene/acrylonitrile (SAN) or acrylonitrile/butadiene/styrene (ABS).Polyester and polyamide are especially preferred. More especiallypreferred are linear aromatic polyesters, which can be obtained bypolycondensation of terephthalic acid and glycols, especially ethyleneglycol, or condensation products of terephthalic acid and1,4-bis(hydroxymethyl)cyclohexane, for example polyethyleneterephthalate (PET) or polybutylene terephthalate (PBT); alsopolycarbonates, e.g. those obtained fromα,α-dimethyl-4,4-dihydroxy-diphenylmethane and phosgene, or polymersbased on polyvinyl chloride and also on polyamide, for example polyamide6 or polyamide 6.6.

Since the compounds of formula (I) according to the invention contain atleast 4 active H atoms (NH and OH groups, respectively), mixing the dyewith the monomers and incorporation thereof in the form of a comonomerdirectly into the polymer skeleton is possible, provided that themonomers contain reactive groups that react with the active hydrogenatoms of the NH, OH or SH groups. Examples of such monomers includeepoxides (epoxy resins), isocyanates (polyurethanes) and carboxylic acidchlorides (polyamides, polyesters).

The invention accordingly relates also to a method of producingmass-coloured plastics or polymeric colour particles that comprisescausing a mixture comprising at least one monomer that contains at leastone NH— or OH-reactive group and is capable of polymerisation,polyaddition or polycondensation reactions to react with at least onecompound of formula I.

The present invention relates also to the use of compounds of formula Iin the production of mass-coloured plastics or polymeric colourparticles and to the plastics and polymeric colour particles colouredusing the compounds of formula I.

The dyes according to the invention impart to the above-mentionedmaterials, especially polyester materials, level colour shades of hightinctorial strength that have good in-use fastness properties,especially very good high-temperature light fastness.

The dyes according to the invention can also readily be used togetherwith other dyes to produce blended shades.

The dyes according to the invention can furthermore be used for coatingapplications of any kind.

The azo dyes of formula (I) according to the invention are furthermoresuitable as colorants in the production of colour filters, especiallyfor visible light in the range from 400 to 700 nm, for liquid crystaldisplays (LCDs) or charge combined devices (CCDs).

The production of colour filters by sequential application of a red,blue and green colorant to a suitable substrate, for example amorphoussilicon, is described in GB-A 2 182 165. The colour filters can becoated, for example, using inks, especially printing inks, that comprisethe azo dyes according to the invention, or can be produced, forexample, by blending the azo dyes according to the invention withchemically, thermally or photolytically structurable high molecularweight material. The further production can be carried out, for example,analogously to EP-A 654 711 by application to a substrate, such as anLCD, followed by photo-structuring and development. Other documents thatdescribe the production of colour filters include U.S. Pat. No.5,624,467, Displays 14/2, 115 (1993) and WO 98/45756.

The colour filters that are produced for liquid crystal displays (LCDs)using the azo dyes according to the invention are distinguished by hightransmission of colour dots.

The invention relates also to the use of an azo dye according to theinvention as a colorant in the production of colour filters.

The following Examples serve to illustrate the invention.

I. PREPARATION EXAMPLES

I.1 Compound of Formula (Ia)

A. Synthesis of 2,6-bis(2-hydroxyethylamino)-3-cyano-4-methylpyridine

1075 ml of ethanolamine are introduced at room temperature (RT) into aplane-ground flask. Using a powder funnel, 472.3 g of2,6-dichloro-3-cyano-4-methylpyridine are introduced in the course of 30min. The exothermic reaction is cooled using a water bath. The productquickly dissolves, the exothermic reaction subsiding. After 30 minutesthe internal temperature is 30° C., and a further 100 ml of ethanolamineis added.

The solution is stirred for a further 10 min. while cooling with a waterbath, and subsequently heated to an internal temperature of 115° C.After 20 min. the internal temperature reaches 135° C., and the flask iscooled again using a water bath. The reaction mixture is left to standovernight at RT and then stirred for a further 4 hours at 115° C. Whilecooling with an ice bath, the reaction solution is subsequently pouredinto 5 litres of 1N hydrochloric acid; after a short time a precipitateis formed. 1 litre of 1N hydrochloric acid is added and the light brownsuspension is stirred for 2 hours, the internal temperature rising toRT. The precipitate is filtered off, washed with 1 litre of 1Nhydrochlirc acid and 10 litres of water and subsequently dried for 2days at 50° C. in a vacuum drying chamber.

Yield: 551.8 g (93.4%)

B. Diazotization with 2-aminodiphenylsulfone

14.7 g of 2-aminodiphenylsulfone are suspended in 160 ml of glacialacetic acid. 18 g of 32% hydrochloric acid are then added and, at 15–18°C., 15.3 ml of 4N sodium nitrite solution are added dropwise. Afterstirring for 1 hour at 15–18° C., excess nitrite is destroyed by theaddition of 10% sulfamic acid.

14.5 g of 2,6-bis(2-hydroxyethylamino)-3-cyano-4-methylpyridine areintroduced into 250 ml of water. After the dropwise addition of 5 dropsof 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 10 g of 32% hydrochloricacid, the solution is cooled to 15° C. 50 g of ice, the solution of thediazonium salt of 2-aminodiphenylsulfone and 100 ml of water are thenadded. The reaction mixture is stirred for 1 hour, and then a further200 ml of water is added. The precipitate is filtered off, washed anddried.

Yield: 29.1 g (100%)

I.2 Compound of Formula (Ib)

7.5 g of 2-aminobenzenesulfonic acid phenyl ester are dissolved in 80 mlof glacial acetic acid. Subsequently, 8 g of 32% hydrochloric acid and,at 15–20° C., 7.6 ml of 4N sodium nitrite solution, are added dropwise.After stirring for 1 hour at 15–20° C., excess nitrite is destroyed bythe addition of 10% sulfamic acid.

7.1 g of 2,6-bis(2-hydroxyethylamino)-3-cyano-4-methylpyridine areintroduced into 100 ml of water. After the dropwise addition of 2 dropsof 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 5 g of 32% hydrochloricacid, the solution is cooled to 15° C. The solution of the diazoniumsalt of 2-aminobenzenesulfonic acid phenyl ester is then added at 15–20°C. The suspension is stirred for 1 hour without cooling, and then 50 mlof water are added. The precipitate is filtered off, washed and dried.

Yield: 14.2 g (96%)

I.3 Compound of Formula (Ic)

11.6 g of 2-aminobenzenesulfonic acid N-phenyl-N-ethylamide aredissolved in 100 ml of glacial acetic acid. Subsequently, 14 g of 32%hydrochloric acid and, at 15–20° C., 10 ml of 4N sodium nitritesolution, are added dropwise. After stirring for 1 hour at 15–20° C.,excess nitrite is destroyed by the addition of 10% sulfamic acid.

9.9 g of 2,6-bis(2-hydroxyethylamino)-3-cyano-4-methylpyridine areintroduced into 160 ml of water. After the dropwise addition of 5 dropsof 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 6.6 g of 32% hydrochloricacid, 50 g of ice are added. The solution of the diazonium salt of2-aminobenzenesulfonic acid N-phenyl-N-ethylamide is then added dropwiseat 15–20° C. The suspension is stirred for 1 hour without cooling andthen 100 ml of water are added. The precipitate is filtered off, washedand dried and recrystallised from ethanol.

Yield: 18.2 g (87%)

II. APPLICATION EXAMPLES

II.1. Production of a Colour Filter for Liquid Crystal Displays (LCDs)

In a 100 ml glass vessel containing 83.3 g of zirconium ceramic beads,2.8 g of the azo dye according to Example I.1, 0.28 g of Solsperse®5000, 4.10 g of Disperbyk® 161 (dispersing agent, 30% solution of a highmolecular weight block copolymer, containing groups having affinity forthe pigment, in n-butyl acetate/1-methoxy-2-propyl acetate 1:6, BYKChemie) and 14.62 g of 1-methoxy-2-propyl acetate (MPA) are stirred at23° C. for 10 minutes at 1000 revs/min. and for 180 minutes at 3000revs/min. using a Dispermat. After the addition of 4.01 g of an acrylatepolymer binder (35% solution in MPA), stirring is carried out at roomtemperature for 30 minutes at 3000 revs/min. Following removal of thebeads, the dispersion is diluted with an equal weight of MPA.

Using a spin-coating apparatus, a glass substrate (Corning type 1737-F)is coated with the resulting dispersion and centrifuged for 30 secondsat 1000 revs/min. The layer is dried on a hot plate for 2 minutes at100° C. and for 5 minutes at 200° C. The resulting layer thickness is0.4 μm.

The following azo dyes (Tables 1–18), which are likewise suitable formass-colouring plastics, can be prepared analogously to Example I.1:

TABLE 1

R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 2

R₁ = R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH,—NH—(CH₂CH₂)—S—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂, —NH—CH₂—CON(CH₂CH₂OH)₂,—NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 3

R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 4

R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 5

R₁ = R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH,—NH—(CH₂CH₂)—S—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂, —NH—CH₂—CON(CH₂CH₂OH)₂,—NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 6

R₂ = —NH—(CH₂CH₂)—OH. —NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 7

R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 8

R₁ = R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH,—NH—(CH₂CH₂)—S—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂, —NH—CH₂—CON(CH₂CH₂OH)₂,—NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 9

R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 10

R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 11

R₁ = R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH,—NH—(CH₂CH₂)—S—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂, —NH—CH₂—CON(CH₂CH₂OH)₂,—NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 12

R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 13

R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 14

R₁ = R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH,—NH—(CH₂CH₂)—S—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂, —NH—CH₂—CON(CH₂CH₂OH)₂,—NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 15

R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 16

R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 17

R₁ = R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH,—NH—(CH₂CH₂)—S—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂, —NH—CH₂—CON(CH₂CH₂OH)₂,—NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

TABLE 18

R₂ = —NH—(CH₂CH₂)—OH, —NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

1. An azo dye of formula I

wherein R₁ and R₂ are each independently of the other —NH—(CH₂CH₂)—OH,—NH—CH₂—CHOH—CH₂—OH, —NH—(CH₂CH₂)—S—(CH₂CH₂)—OH,—NH—(CH₂CH₂)—NH—(CH₂CH₂)—OH, —NH—(CH₂CH₂)—NH₂, —NH—CH₂—CHOH—CH₂—NH₂,—NH—CH₂—CON(CH₂CH₂OH)₂, —NH—CH₂CH₂—CON(CH₂CH₂OH)₂,

R₃ is —CN or —CONH₂, R₄ is methyl or trifluoromethyl, R₅ is —CF₃,—COOC₂H₅,

R₆ is hydrogen or chlorine, and R₇ is hydrogen, chlorine, bromine or—NO₂.
 2. An azo dye of formula I according to claim 1 wherein R₃ is —CNand R₄ is methyl.
 3. An azo dye of formula I according to claim 1wherein R₁ and R₂ are


4. An azo dye of formula I according to claim 1 wherein R₇ is hydrogen.5. An azo dye of formula Ia, Ib, Ic or Id


6. A process for the preparation of an azo dye of formula (I) accordingto claim 1, which comprises diazotizing a compound of formula (II)

wherein R₅, R₆ and R₇ are as defined in claim 1, according to aconventional method and then coupling the diazotized compound with acoupling component of formula III

wherein R₁, R₂ R₃ and R₄ are as defined in claim
 1. 7. A method ofproducing mass-coloured plastics or polymeric colour particles thatcomprises mixing a high molecular weight organic material with atinctorially effective amount of at least one azo dye of formula (I)according to claim
 1. 8. A method of producing mass-coloured plastics orpolymeric colour particles that comprises causing a mixture comprisingat least one monomer that contains at least one NH-, CH or SH-reactivegroup and is capable of polymerisation, polyaddition or polycondensationreactions to react with at least one compound of formula I according toclaim
 1. 9. Plastics or polymeric colour particles coloured inaccordance with a method according to claim
 7. 10. Plastics or polymericcolour particles coloured in accordance with a method according to claim8.
 11. A method of producing colour filters that comprises coating asubstrate with a high molecular weight organic material that contains atinctorially effective amount of at least one azo dye of formula (I)according to claim 1.